System, method and program to migrate a virtual machine

Abstract

A system, method and program product for migrating a first virtual machine from a first real computer to a second real computer or from a first LPAR to a second LPAR in a same real computer. Before migration, the first virtual machine comprises an operating system and an application in a first private memory private to the first virtual machine. A communication queue of the first virtual machine resides in a shared memory shared by the first and second computers or the first and second LPARs. The operating system and application are copied from the first private memory to the shared memory. The operating system and application are copied from the shared memory to a second private memory private to the first virtual machine in the second computer or second LPAR. Then, the first virtual machine is resumed in the second computer or second LPAR.

Description

BACKGROUND OF THE INVENTION [0001] The invention relates generally to computer systems, and deals more particularly with migration of a virtual machine within a same real computer from one logical partition to another, or from one real computer to another real computer. [0002] A virtual machine operating system is well known today, and includes a hypervisor program, and separate virtual machines formed by the hypervisor. In an IBM z / VM operating system, the hypervisor program is called the Control Program (“CP”). Each virtual machine is also called a “user portion” or “guest”. A virtual machine is a virtual sharing / partitioning of computer resources such as processor(s), memory, storage and I / O (i.e. network cards, printers and displays.) A guest operating system executes / runs on each virtual machine. One or more applications run on each guest operating system. [0003] It was also known to logically partition a computer by logically dividing the real computer resources. The user defi...

AI Technical Summary

Problems solved by technology

While this arrangement provides a shared work queue, it requires a high overhead communication protocol to both send a work item to the work queue and obtain a work item from the work queue.

Any messages contained in memory within the physical communication card and not yet read by the original computer would not be available to this other personal computer.

Also, messages sent to the physical communication card during its movement from the original computer to the other personal computer would be lost.

However, any I / O requests currently in progress on the physical block I / O card during its movement from the original computer to the other personal computer would be lost.

There was no ability to handle “in flight” I / O, i.e. communications and data sent from one virtual machine to another virtual machine but not yet received or processed by the other virtual machine.

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